dfilter: Make string slices a return an FT_STRING

Allow string slices (indexing) to work with internationalized
strings. The old behavior of indexing on byte boundaries can
be obtained using raw slices.

2 files changed, 52 insertions, 5 deletions

diff --git a/test/suite_dfilter/dfiltertest.py b/test/suite_dfilter/dfiltertest.py
index c464c5edaa..6a92c8f337 100644
--- a/test/suite_dfilter/dfiltertest.py
+++ b/test/suite_dfilter/dfiltertest.py
@@ -8,7 +8,7 @@ import pytest
 
 @pytest.fixture
 def dfilter_cmd(cmd_tshark, capture_file, request):
-    def wrapped(dfilter, frame_number=None):
+    def wrapped(dfilter, frame_number=None, prefs=None):
         cmd = [
             cmd_tshark,
             "-n",       # No name resolution
@@ -24,6 +24,11 @@ def dfilter_cmd(cmd_tshark, capture_file, request):
             "-Y",       # packet display filter (used to be -R)
             dfilter
         ])
+        if prefs:
+            cmd.extend([
+            "-o",
+            prefs
+        ])
         return cmd
     return wrapped
 
@@ -34,9 +39,9 @@ def cmd_dftest(program):
 
 @pytest.fixture
 def checkDFilterCount(dfilter_cmd, base_env):
-    def checkDFilterCount_real(dfilter, expected_count):
+    def checkDFilterCount_real(dfilter, expected_count, prefs=None):
         """Run a display filter and expect a certain number of packets."""
-        output = subprocess.check_output(dfilter_cmd(dfilter),
+        output = subprocess.check_output(dfilter_cmd(dfilter, prefs=prefs),
                                          universal_newlines=True,
                                          stderr=subprocess.STDOUT,
                                          env=base_env)
@@ -49,9 +54,9 @@ def checkDFilterCount(dfilter_cmd, base_env):
 
 @pytest.fixture
 def checkDFilterCountWithSelectedFrame(dfilter_cmd, base_env):
-    def checkDFilterCount_real(dfilter, expected_count, selected_frame):
+    def checkDFilterCount_real(dfilter, expected_count, selected_frame, prefs=None):
         """Run a display filter and expect a certain number of packets."""
-        output = subprocess.check_output(dfilter_cmd(dfilter, frame_number=selected_frame),
+        output = subprocess.check_output(dfilter_cmd(dfilter, frame_number=selected_frame, prefs=prefs),
                                          universal_newlines=True,
                                          stderr=subprocess.STDOUT,
                                          env=base_env)
diff --git a/test/suite_dfilter/group_string.py b/test/suite_dfilter/group_string.py
index e8694010ce..8d77b3e662 100644
--- a/test/suite_dfilter/group_string.py
+++ b/test/suite_dfilter/group_string.py
@@ -196,3 +196,45 @@ class TestDfilterStringz:
     def test_stringz_3(self, checkDFilterCount):
         dfilter = 'tftp.type == junk'
         checkDFilterCount(dfilter, 0)
+
+class TestDfilterStringIndex:
+    trace_file = "data-utf8.pcap"
+
+    def test_index_1(self, checkDFilterCount):
+        dfilter = 'data.text[3] == "á"'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+
+    def test_index_2(self, checkDFilterCount):
+        dfilter = 'data.text[3] == "a"'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 0, prefs)
+
+    def test_index_3(self, checkDFilterCount):
+        dfilter = 'data.text[40:] == "cão preguiçoso"'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+
+    def test_index_4(self, checkDFilterCount):
+        # Byte offset
+        dfilter = '@data.text[41:] == "cão preguiçoso"'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+
+    def test_index_5(self, checkDFilterCount):
+        # Byte offset
+        dfilter = '@data.text[41:] == 63:c3:a3:6f:20:70:72:65:67:75:69:c3:a7:6f:73:6f'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+
+    def test_strlen_1(self, checkDFilterCount):
+        dfilter = 'len(data.text) == 54'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+
+    def test_strlen_2(self, checkDFilterCount):
+        # Byte length
+        dfilter = 'len(@data.text) == 57'
+        prefs = "data.show_as_text:true"
+        checkDFilterCount(dfilter, 1, prefs)
+